Arstechnica writes, regarding the Force Touch Trackpad in the updated 13-inch Retina MacBook Pro:
The only external change to the Pro is the addition of Apple’s Force Touch Trackpad, originally developed for the Retina MacBook. To accommodate that system’s thinness, the trackpad doesn’t physically move as most current trackpads do. This isn’t something that Apple did first—Synaptics has shipped a clickless ForcePad for years—but Apple’s implementation is the first that approximates the feel of a standard trackpad. It’s also pressure sensitive and can respond differently depending on how hard you press down.
I can’t emphasize enough how true it is. I went to Best Buy yesterday to try out the Force Trackpad and it’s indistinguishable from a real click, except that you now have the option to click “deeper”. It basically adds a Z-depth to the existing multitouch trackpad paradigm and it’s super, super cool.
I wouldn’t recommend going and buying a new laptop just to have this feature, but given that Apple’s laptops already outperform competitors when it comes to trackpad functionality, this is like leapfrogging the competition before they even catch up with you. It’ll be especially great once third-party developers start playing with it.